1. Field of the Invention
The present invention relates to advertising displays and more particularly to a fixture and method for creating mosaic transparencies used for sequentially exhibiting multiple images in an advertising display.
2. Description of the Prior Art
Advertising allows various business organizations to convey information concerning their products to consumers. Creating a market worth billions of dollars each year, advertising agencies continually seek new and innovative ways to "deliver their message" to consumers. Whether by billboard, bus, or blimp, consumers often react to these messages by purchasing the represented products. Thus, the need for product exposure is often critical to the success of a product.
Comprising a small but critical segment of the advertising industry is "point of sale" advertising where descriptive product exposure occurs near the product itself inside the store. Such exposure often involves colorful posters or sightly banners to attract attention. In addition, video displays are often used which may illustrate the uses or benefits of a product. However, due to limitations on the extent of space available to attract the attention of potential customers, only limited numbers of such banners and video representations can be displayed in a defined area. As a result, compact advertising devices have been proposed to sequentially display several different images for set periods of time on a single screen to provide advertisers with greater flexibility for a greater variety of exposure.
Utilizing attention grabbing animated displays and multiple display advertisements to improve communication of an advertiser's message, sequential image display systems take many forms. Display devices including templates with patterns of apertures which define numbers, letters or figures when they are illuminated by back lighting have been described. See, e.g., Hildburgh, U.S. Pat. No. 1,172,455, and Kass, U.S. Pat. No. 2,982,038. There have also been described display devices including transparency sheets which have images thereon to be illuminated by back lighting for projection through an overlay mask which selectively blocks the back lighting from illuminating certain areas of the transparency sheets. See, e.g., Elvestrom, U.S. Pat. No. 3,000,125, Fukui, U.S. Pat. No. 3,683,525, and Hasala, U.S. Pat. No. 3,742,631.
In addition, devices have been proposed which include a translucent image screen made up of a mosaic of discrete images formed by relatively small interlaced translucent pixels or window segments which are arranged in uniform groups. Pixels corresponding to a discrete image occupy the same relative position in each group and bear corresponding relative magnitudes of translucency. An opaque overlay screen having a uniform pattern of transparent display apertures may then cover the image screen. Providing a masking function, the opaque screen blocks back lighting from projecting through the image screen, except for the areas defined by the display apertures. The uniformly patterned display apertures are then aligned with pixels which correspond to a discrete image and the discrete image is thereby displayed due to the back light shining through the areas of the image screen defined by the display apertures. Selectively shifted on the image screen such that the display apertures align with the pixels of a different image, the opaque screen may be repositioned. Thus, each discrete image may be sequentially displayed.
A device of this general description is shown in U.S. Pat. No. 4,897,802 to Atkinson et al., assigned to the assignee of the present application. The device, as described in that patent, exhibits excellent operational characteristics, sequentially displaying discrete images exposed onto a single transparency.
The transparency used in the Atkinson display device is fabricated according to one of two methods by using a fixture disclosed in the Atkinson patent. The fixture is part of an exposure system, comprising a camera and a framework for mounting a projector. A mirrored, folded light path is provided through the framework for columnating the light to obtain full size pixels. This mirrored path is necessary to minimize divergence of the projected light from the light source, often causing shadowing and oversizing of exposed pixels due to the relatively small sizing of the mask apertures through which the projected light passes. The system further includes a mask and a moveable vacuum mount with film mounted thereon. Corresponding to the pixel spacing, the mount is moveable 0.013 inches right, left, up and down. Although beneficial in that the fixture offers a movable mount, enabling efficient repositioning of the film to allow all four exposures to be made onto the single sheet of film, the device is large and relatively complex due to the mirrored path.
Having fabrication fixtures structurally similar to the fixture disclosed in Atkinson, "step and repeat" exposure systems often allow multiple exposures from an original negative and generally include frameworks having film mounting portions along with hinged masked frames allowing light to expose only certain sections of film. Such devices are illustrated in U.S. Pat. Nos. 2,605,675 to Mourfield, 2,763,182 to Urban, 3,635,560 to Hulen, 3,684,370 to Yin and 3,927,942 to Byers. While these fixtures often provide for relative movement between the film and the mask, such movement is often for "registry" purposes to align a new section of unexposed film for exposure of an image to that particular section.
Step and repeat exposure methods are often used to quickly and efficiently expose duplicate images onto single sheets of film. Using a multiple image placement camera to expose individually spaced pictures, U.S. Pat. Nos. 2,763,182, 3,635,560, and 2,605,675 illustrate the general "step and repeat" method. First, a particular negative is exposed onto an unmasked portion of film. Next, a special fixture precisely moves either the film or a mask to the corresponding location for the next image to be exposed. The process repeats as desired until the film is completely exposed. Although extremely efficient and adequate to expose multiple images onto single sheets of film, the disclosed methods do not create images which are interlaced among other images throughout the film surface for efficient display of selected ones of such images for set periods of time. Rather, each print is set onto its own particular section of film, often resulting in rows and columns of pictures.
In addition to teaching the basic display apparatus and mosaic fabrication fixture, the Atkinson patent further discloses methods of fabricating the mosaic image screens used with the display device. One such method begins by supplying an image bearing negative along with a full size sheet of film. Critical to the fabrication process, a fixture having an opaque stationary gridlike mask is provided to secure the film. The mask allows "segments" of the overall image to be exposed onto the film, while still preserving the overall image likeness. The exposure process begins by projecting the image onto the masked film thus producing a transparency with the image. Next, a new negative is supplied along with another sheet of film, and the process repeated. After four such exposures, the resulting transparencies are stacked with the exposed "groups" offset from one another to cooperate to form a mosaic. The mosaic is then photographically reproduced to generate a single transparency with the mosaic image.
A second method disclosed by the Atkinson patent simplifies the above procedure somewhat by making use of the mirrored path exposure fixture described previously. The method duplicates the steps of the first method except for the "stacking" operation of the resulting transparencies. Instead, the fixture is configured such that one sheet of film is affixed to a movable platen, and repositioned after each exposure so that all four images become exposed onto the same sheet during the initial exposure process.
Although beneficial for their intended purposes, the above mentioned mosaic fabrication methods have limitations which often compromise the quality of the finished product. One such limitation involves a phenomena commonly referred to as "white flash". Representing bright border streaks adjacent to opaque pixel boundary lines, "white flash" detracts from the quality of the image presentation during an image transition, causing attention to the bright aberrations momentarily observable on the display viewing surface. Careful exposure techniques using the hereinabove methods may result in a transparency free from "white flash", however, such techniques often involve exact alignment of new exposures or the exposure mask to prevent exposure voids between pixels. However, such time consuming care creates a more costly finished product.
Thus the need exists for a simple and efficient display mosaic fabrication fixture having the capability of controllably and precisely relatively positioning a mask relative to a sheet of film for creating a display mosaic image characterized by individual image pixels interspersed with pixels of other images over the face of the sheet of film for subsequent selected illumination of the selected pixels of the respective images. Additionally, the need exists for a more efficient method for creating mosaic transparencies free from "white flash".